ab42316c2f
vm_pageout_scan(). Rationale: I don't like leaving a busy page in the cache queue with neither the vm object nor the vm page queues lock held. - Assert that the page is active in vm_pageout_page_stats().
1797 lines
44 KiB
C
1797 lines
44 KiB
C
/*
|
|
* Copyright (c) 1991 Regents of the University of California.
|
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* All rights reserved.
|
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*
|
|
* This code is derived from software contributed to Berkeley by
|
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* The Mach Operating System project at Carnegie-Mellon University.
|
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*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
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* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
|
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*
|
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* from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
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*/
|
|
|
|
/*
|
|
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
|
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* All rights reserved.
|
|
*
|
|
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
|
|
*
|
|
* Permission to use, copy, modify and distribute this software and
|
|
* its documentation is hereby granted, provided that both the copyright
|
|
* notice and this permission notice appear in all copies of the
|
|
* software, derivative works or modified versions, and any portions
|
|
* thereof, and that both notices appear in supporting documentation.
|
|
*
|
|
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
|
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
|
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
|
*
|
|
* Carnegie Mellon requests users of this software to return to
|
|
*
|
|
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
|
* School of Computer Science
|
|
* Carnegie Mellon University
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|
* Pittsburgh PA 15213-3890
|
|
*
|
|
* any improvements or extensions that they make and grant Carnegie the
|
|
* rights to redistribute these changes.
|
|
*/
|
|
|
|
/*
|
|
* GENERAL RULES ON VM_PAGE MANIPULATION
|
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*
|
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* - a pageq mutex is required when adding or removing a page from a
|
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* page queue (vm_page_queue[]), regardless of other mutexes or the
|
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* busy state of a page.
|
|
*
|
|
* - a hash chain mutex is required when associating or disassociating
|
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* a page from the VM PAGE CACHE hash table (vm_page_buckets),
|
|
* regardless of other mutexes or the busy state of a page.
|
|
*
|
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* - either a hash chain mutex OR a busied page is required in order
|
|
* to modify the page flags. A hash chain mutex must be obtained in
|
|
* order to busy a page. A page's flags cannot be modified by a
|
|
* hash chain mutex if the page is marked busy.
|
|
*
|
|
* - The object memq mutex is held when inserting or removing
|
|
* pages from an object (vm_page_insert() or vm_page_remove()). This
|
|
* is different from the object's main mutex.
|
|
*
|
|
* Generally speaking, you have to be aware of side effects when running
|
|
* vm_page ops. A vm_page_lookup() will return with the hash chain
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|
* locked, whether it was able to lookup the page or not. vm_page_free(),
|
|
* vm_page_cache(), vm_page_activate(), and a number of other routines
|
|
* will release the hash chain mutex for you. Intermediate manipulation
|
|
* routines such as vm_page_flag_set() expect the hash chain to be held
|
|
* on entry and the hash chain will remain held on return.
|
|
*
|
|
* pageq scanning can only occur with the pageq in question locked.
|
|
* We have a known bottleneck with the active queue, but the cache
|
|
* and free queues are actually arrays already.
|
|
*/
|
|
|
|
/*
|
|
* Resident memory management module.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/vmmeter.h>
|
|
#include <sys/vnode.h>
|
|
|
|
#include <vm/vm.h>
|
|
#include <vm/vm_param.h>
|
|
#include <vm/vm_kern.h>
|
|
#include <vm/vm_object.h>
|
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#include <vm/vm_page.h>
|
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#include <vm/vm_pageout.h>
|
|
#include <vm/vm_pager.h>
|
|
#include <vm/vm_extern.h>
|
|
#include <vm/uma.h>
|
|
#include <vm/uma_int.h>
|
|
|
|
/*
|
|
* Associated with page of user-allocatable memory is a
|
|
* page structure.
|
|
*/
|
|
|
|
struct mtx vm_page_queue_mtx;
|
|
struct mtx vm_page_queue_free_mtx;
|
|
|
|
vm_page_t vm_page_array = 0;
|
|
int vm_page_array_size = 0;
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|
long first_page = 0;
|
|
int vm_page_zero_count = 0;
|
|
|
|
/*
|
|
* vm_set_page_size:
|
|
*
|
|
* Sets the page size, perhaps based upon the memory
|
|
* size. Must be called before any use of page-size
|
|
* dependent functions.
|
|
*/
|
|
void
|
|
vm_set_page_size(void)
|
|
{
|
|
if (cnt.v_page_size == 0)
|
|
cnt.v_page_size = PAGE_SIZE;
|
|
if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0)
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panic("vm_set_page_size: page size not a power of two");
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|
}
|
|
|
|
/*
|
|
* vm_page_startup:
|
|
*
|
|
* Initializes the resident memory module.
|
|
*
|
|
* Allocates memory for the page cells, and
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|
* for the object/offset-to-page hash table headers.
|
|
* Each page cell is initialized and placed on the free list.
|
|
*/
|
|
vm_offset_t
|
|
vm_page_startup(vm_offset_t starta, vm_offset_t enda, vm_offset_t vaddr)
|
|
{
|
|
vm_offset_t mapped;
|
|
vm_size_t npages;
|
|
vm_paddr_t page_range;
|
|
vm_paddr_t new_end;
|
|
int i;
|
|
vm_paddr_t pa;
|
|
int nblocks;
|
|
vm_paddr_t last_pa;
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|
|
|
/* the biggest memory array is the second group of pages */
|
|
vm_paddr_t end;
|
|
vm_paddr_t biggestsize;
|
|
int biggestone;
|
|
|
|
vm_paddr_t total;
|
|
vm_size_t bootpages;
|
|
|
|
total = 0;
|
|
biggestsize = 0;
|
|
biggestone = 0;
|
|
nblocks = 0;
|
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vaddr = round_page(vaddr);
|
|
|
|
for (i = 0; phys_avail[i + 1]; i += 2) {
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|
phys_avail[i] = round_page(phys_avail[i]);
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|
phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
|
|
}
|
|
|
|
for (i = 0; phys_avail[i + 1]; i += 2) {
|
|
vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
|
|
|
|
if (size > biggestsize) {
|
|
biggestone = i;
|
|
biggestsize = size;
|
|
}
|
|
++nblocks;
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total += size;
|
|
}
|
|
|
|
end = phys_avail[biggestone+1];
|
|
|
|
/*
|
|
* Initialize the locks.
|
|
*/
|
|
mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF);
|
|
mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL,
|
|
MTX_SPIN);
|
|
|
|
/*
|
|
* Initialize the queue headers for the free queue, the active queue
|
|
* and the inactive queue.
|
|
*/
|
|
vm_pageq_init();
|
|
|
|
/*
|
|
* Allocate memory for use when boot strapping the kernel memory
|
|
* allocator.
|
|
*/
|
|
bootpages = UMA_BOOT_PAGES * UMA_SLAB_SIZE;
|
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new_end = end - bootpages;
|
|
new_end = trunc_page(new_end);
|
|
mapped = pmap_map(&vaddr, new_end, end,
|
|
VM_PROT_READ | VM_PROT_WRITE);
|
|
bzero((caddr_t) mapped, end - new_end);
|
|
uma_startup((caddr_t)mapped);
|
|
|
|
/*
|
|
* Compute the number of pages of memory that will be available for
|
|
* use (taking into account the overhead of a page structure per
|
|
* page).
|
|
*/
|
|
first_page = phys_avail[0] / PAGE_SIZE;
|
|
page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
|
|
npages = (total - (page_range * sizeof(struct vm_page)) -
|
|
(end - new_end)) / PAGE_SIZE;
|
|
end = new_end;
|
|
|
|
/*
|
|
* Initialize the mem entry structures now, and put them in the free
|
|
* queue.
|
|
*/
|
|
new_end = trunc_page(end - page_range * sizeof(struct vm_page));
|
|
mapped = pmap_map(&vaddr, new_end, end,
|
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VM_PROT_READ | VM_PROT_WRITE);
|
|
vm_page_array = (vm_page_t) mapped;
|
|
phys_avail[biggestone + 1] = new_end;
|
|
|
|
/*
|
|
* Clear all of the page structures
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|
*/
|
|
bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
|
|
vm_page_array_size = page_range;
|
|
|
|
/*
|
|
* Construct the free queue(s) in descending order (by physical
|
|
* address) so that the first 16MB of physical memory is allocated
|
|
* last rather than first. On large-memory machines, this avoids
|
|
* the exhaustion of low physical memory before isa_dmainit has run.
|
|
*/
|
|
cnt.v_page_count = 0;
|
|
cnt.v_free_count = 0;
|
|
for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
|
|
pa = phys_avail[i];
|
|
last_pa = phys_avail[i + 1];
|
|
while (pa < last_pa && npages-- > 0) {
|
|
vm_pageq_add_new_page(pa);
|
|
pa += PAGE_SIZE;
|
|
}
|
|
}
|
|
return (vaddr);
|
|
}
|
|
|
|
void
|
|
vm_page_flag_set(vm_page_t m, unsigned short bits)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->flags |= bits;
|
|
}
|
|
|
|
void
|
|
vm_page_flag_clear(vm_page_t m, unsigned short bits)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->flags &= ~bits;
|
|
}
|
|
|
|
void
|
|
vm_page_busy(vm_page_t m)
|
|
{
|
|
KASSERT((m->flags & PG_BUSY) == 0,
|
|
("vm_page_busy: page already busy!!!"));
|
|
vm_page_flag_set(m, PG_BUSY);
|
|
}
|
|
|
|
/*
|
|
* vm_page_flash:
|
|
*
|
|
* wakeup anyone waiting for the page.
|
|
*/
|
|
void
|
|
vm_page_flash(vm_page_t m)
|
|
{
|
|
if (m->flags & PG_WANTED) {
|
|
vm_page_flag_clear(m, PG_WANTED);
|
|
wakeup(m);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_page_wakeup:
|
|
*
|
|
* clear the PG_BUSY flag and wakeup anyone waiting for the
|
|
* page.
|
|
*
|
|
*/
|
|
void
|
|
vm_page_wakeup(vm_page_t m)
|
|
{
|
|
KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!"));
|
|
vm_page_flag_clear(m, PG_BUSY);
|
|
vm_page_flash(m);
|
|
}
|
|
|
|
void
|
|
vm_page_io_start(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->busy++;
|
|
}
|
|
|
|
void
|
|
vm_page_io_finish(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->busy--;
|
|
if (m->busy == 0)
|
|
vm_page_flash(m);
|
|
}
|
|
|
|
/*
|
|
* Keep page from being freed by the page daemon
|
|
* much of the same effect as wiring, except much lower
|
|
* overhead and should be used only for *very* temporary
|
|
* holding ("wiring").
|
|
*/
|
|
void
|
|
vm_page_hold(vm_page_t mem)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
mem->hold_count++;
|
|
}
|
|
|
|
void
|
|
vm_page_unhold(vm_page_t mem)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
--mem->hold_count;
|
|
KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
|
|
if (mem->hold_count == 0 && mem->queue == PQ_HOLD)
|
|
vm_page_free_toq(mem);
|
|
}
|
|
|
|
/*
|
|
* vm_page_free:
|
|
*
|
|
* Free a page
|
|
*
|
|
* The clearing of PG_ZERO is a temporary safety until the code can be
|
|
* reviewed to determine that PG_ZERO is being properly cleared on
|
|
* write faults or maps. PG_ZERO was previously cleared in
|
|
* vm_page_alloc().
|
|
*/
|
|
void
|
|
vm_page_free(vm_page_t m)
|
|
{
|
|
vm_page_flag_clear(m, PG_ZERO);
|
|
vm_page_free_toq(m);
|
|
vm_page_zero_idle_wakeup();
|
|
}
|
|
|
|
/*
|
|
* vm_page_free_zero:
|
|
*
|
|
* Free a page to the zerod-pages queue
|
|
*/
|
|
void
|
|
vm_page_free_zero(vm_page_t m)
|
|
{
|
|
vm_page_flag_set(m, PG_ZERO);
|
|
vm_page_free_toq(m);
|
|
}
|
|
|
|
/*
|
|
* vm_page_sleep_if_busy:
|
|
*
|
|
* Sleep and release the page queues lock if PG_BUSY is set or,
|
|
* if also_m_busy is TRUE, busy is non-zero. Returns TRUE if the
|
|
* thread slept and the page queues lock was released.
|
|
* Otherwise, retains the page queues lock and returns FALSE.
|
|
*/
|
|
int
|
|
vm_page_sleep_if_busy(vm_page_t m, int also_m_busy, const char *msg)
|
|
{
|
|
int is_object_locked;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) {
|
|
vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
|
|
/*
|
|
* Remove mtx_owned() after vm_object locking is finished.
|
|
*/
|
|
if ((is_object_locked = m->object != NULL &&
|
|
mtx_owned(&m->object->mtx)))
|
|
mtx_unlock(&m->object->mtx);
|
|
msleep(m, &vm_page_queue_mtx, PDROP | PVM, msg, 0);
|
|
if (is_object_locked)
|
|
mtx_lock(&m->object->mtx);
|
|
return (TRUE);
|
|
}
|
|
return (FALSE);
|
|
}
|
|
|
|
/*
|
|
* vm_page_dirty:
|
|
*
|
|
* make page all dirty
|
|
*/
|
|
void
|
|
vm_page_dirty(vm_page_t m)
|
|
{
|
|
KASSERT(m->queue - m->pc != PQ_CACHE,
|
|
("vm_page_dirty: page in cache!"));
|
|
KASSERT(m->queue - m->pc != PQ_FREE,
|
|
("vm_page_dirty: page is free!"));
|
|
m->dirty = VM_PAGE_BITS_ALL;
|
|
}
|
|
|
|
/*
|
|
* vm_page_splay:
|
|
*
|
|
* Implements Sleator and Tarjan's top-down splay algorithm. Returns
|
|
* the vm_page containing the given pindex. If, however, that
|
|
* pindex is not found in the vm_object, returns a vm_page that is
|
|
* adjacent to the pindex, coming before or after it.
|
|
*/
|
|
vm_page_t
|
|
vm_page_splay(vm_pindex_t pindex, vm_page_t root)
|
|
{
|
|
struct vm_page dummy;
|
|
vm_page_t lefttreemax, righttreemin, y;
|
|
|
|
if (root == NULL)
|
|
return (root);
|
|
lefttreemax = righttreemin = &dummy;
|
|
for (;; root = y) {
|
|
if (pindex < root->pindex) {
|
|
if ((y = root->left) == NULL)
|
|
break;
|
|
if (pindex < y->pindex) {
|
|
/* Rotate right. */
|
|
root->left = y->right;
|
|
y->right = root;
|
|
root = y;
|
|
if ((y = root->left) == NULL)
|
|
break;
|
|
}
|
|
/* Link into the new root's right tree. */
|
|
righttreemin->left = root;
|
|
righttreemin = root;
|
|
} else if (pindex > root->pindex) {
|
|
if ((y = root->right) == NULL)
|
|
break;
|
|
if (pindex > y->pindex) {
|
|
/* Rotate left. */
|
|
root->right = y->left;
|
|
y->left = root;
|
|
root = y;
|
|
if ((y = root->right) == NULL)
|
|
break;
|
|
}
|
|
/* Link into the new root's left tree. */
|
|
lefttreemax->right = root;
|
|
lefttreemax = root;
|
|
} else
|
|
break;
|
|
}
|
|
/* Assemble the new root. */
|
|
lefttreemax->right = root->left;
|
|
righttreemin->left = root->right;
|
|
root->left = dummy.right;
|
|
root->right = dummy.left;
|
|
return (root);
|
|
}
|
|
|
|
/*
|
|
* vm_page_insert: [ internal use only ]
|
|
*
|
|
* Inserts the given mem entry into the object and object list.
|
|
*
|
|
* The pagetables are not updated but will presumably fault the page
|
|
* in if necessary, or if a kernel page the caller will at some point
|
|
* enter the page into the kernel's pmap. We are not allowed to block
|
|
* here so we *can't* do this anyway.
|
|
*
|
|
* The object and page must be locked, and must be splhigh.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
vm_page_t root;
|
|
|
|
if (!VM_OBJECT_LOCKED(object))
|
|
GIANT_REQUIRED;
|
|
if (m->object != NULL)
|
|
panic("vm_page_insert: already inserted");
|
|
|
|
/*
|
|
* Record the object/offset pair in this page
|
|
*/
|
|
m->object = object;
|
|
m->pindex = pindex;
|
|
|
|
/*
|
|
* Now link into the object's ordered list of backed pages.
|
|
*/
|
|
root = object->root;
|
|
if (root == NULL) {
|
|
m->left = NULL;
|
|
m->right = NULL;
|
|
TAILQ_INSERT_TAIL(&object->memq, m, listq);
|
|
} else {
|
|
root = vm_page_splay(pindex, root);
|
|
if (pindex < root->pindex) {
|
|
m->left = root->left;
|
|
m->right = root;
|
|
root->left = NULL;
|
|
TAILQ_INSERT_BEFORE(root, m, listq);
|
|
} else {
|
|
m->right = root->right;
|
|
m->left = root;
|
|
root->right = NULL;
|
|
TAILQ_INSERT_AFTER(&object->memq, root, m, listq);
|
|
}
|
|
}
|
|
object->root = m;
|
|
object->generation++;
|
|
|
|
/*
|
|
* show that the object has one more resident page.
|
|
*/
|
|
object->resident_page_count++;
|
|
|
|
/*
|
|
* Since we are inserting a new and possibly dirty page,
|
|
* update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
|
|
*/
|
|
if (m->flags & PG_WRITEABLE)
|
|
vm_object_set_writeable_dirty(object);
|
|
}
|
|
|
|
/*
|
|
* vm_page_remove:
|
|
* NOTE: used by device pager as well -wfj
|
|
*
|
|
* Removes the given mem entry from the object/offset-page
|
|
* table and the object page list, but do not invalidate/terminate
|
|
* the backing store.
|
|
*
|
|
* The object and page must be locked, and at splhigh.
|
|
* The underlying pmap entry (if any) is NOT removed here.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_remove(vm_page_t m)
|
|
{
|
|
vm_object_t object;
|
|
vm_page_t root;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->object == NULL)
|
|
return;
|
|
#ifndef __alpha__
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
#endif
|
|
if ((m->flags & PG_BUSY) == 0) {
|
|
panic("vm_page_remove: page not busy");
|
|
}
|
|
|
|
/*
|
|
* Basically destroy the page.
|
|
*/
|
|
vm_page_wakeup(m);
|
|
|
|
object = m->object;
|
|
|
|
/*
|
|
* Now remove from the object's list of backed pages.
|
|
*/
|
|
if (m != object->root)
|
|
vm_page_splay(m->pindex, object->root);
|
|
if (m->left == NULL)
|
|
root = m->right;
|
|
else {
|
|
root = vm_page_splay(m->pindex, m->left);
|
|
root->right = m->right;
|
|
}
|
|
object->root = root;
|
|
TAILQ_REMOVE(&object->memq, m, listq);
|
|
|
|
/*
|
|
* And show that the object has one fewer resident page.
|
|
*/
|
|
object->resident_page_count--;
|
|
object->generation++;
|
|
|
|
m->object = NULL;
|
|
}
|
|
|
|
/*
|
|
* vm_page_lookup:
|
|
*
|
|
* Returns the page associated with the object/offset
|
|
* pair specified; if none is found, NULL is returned.
|
|
*
|
|
* The object must be locked.
|
|
* This routine may not block.
|
|
* This is a critical path routine
|
|
*/
|
|
vm_page_t
|
|
vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
vm_page_t m;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
m = vm_page_splay(pindex, object->root);
|
|
if ((object->root = m) != NULL && m->pindex != pindex)
|
|
m = NULL;
|
|
return (m);
|
|
}
|
|
|
|
/*
|
|
* vm_page_rename:
|
|
*
|
|
* Move the given memory entry from its
|
|
* current object to the specified target object/offset.
|
|
*
|
|
* The object must be locked.
|
|
* This routine may not block.
|
|
*
|
|
* Note: this routine will raise itself to splvm(), the caller need not.
|
|
*
|
|
* Note: swap associated with the page must be invalidated by the move. We
|
|
* have to do this for several reasons: (1) we aren't freeing the
|
|
* page, (2) we are dirtying the page, (3) the VM system is probably
|
|
* moving the page from object A to B, and will then later move
|
|
* the backing store from A to B and we can't have a conflict.
|
|
*
|
|
* Note: we *always* dirty the page. It is necessary both for the
|
|
* fact that we moved it, and because we may be invalidating
|
|
* swap. If the page is on the cache, we have to deactivate it
|
|
* or vm_page_dirty() will panic. Dirty pages are not allowed
|
|
* on the cache.
|
|
*/
|
|
void
|
|
vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_remove(m);
|
|
vm_page_insert(m, new_object, new_pindex);
|
|
if (m->queue - m->pc == PQ_CACHE)
|
|
vm_page_deactivate(m);
|
|
vm_page_dirty(m);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_select_cache:
|
|
*
|
|
* Find a page on the cache queue with color optimization. As pages
|
|
* might be found, but not applicable, they are deactivated. This
|
|
* keeps us from using potentially busy cached pages.
|
|
*
|
|
* This routine must be called at splvm().
|
|
* This routine may not block.
|
|
*/
|
|
vm_page_t
|
|
vm_page_select_cache(int color)
|
|
{
|
|
vm_page_t m;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
while (TRUE) {
|
|
m = vm_pageq_find(PQ_CACHE, color, FALSE);
|
|
if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
|
|
m->hold_count || m->wire_count ||
|
|
(!VM_OBJECT_TRYLOCK(m->object) &&
|
|
!VM_OBJECT_LOCKED(m->object)))) {
|
|
vm_page_deactivate(m);
|
|
continue;
|
|
}
|
|
return m;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_page_alloc:
|
|
*
|
|
* Allocate and return a memory cell associated
|
|
* with this VM object/offset pair.
|
|
*
|
|
* page_req classes:
|
|
* VM_ALLOC_NORMAL normal process request
|
|
* VM_ALLOC_SYSTEM system *really* needs a page
|
|
* VM_ALLOC_INTERRUPT interrupt time request
|
|
* VM_ALLOC_ZERO zero page
|
|
*
|
|
* This routine may not block.
|
|
*
|
|
* Additional special handling is required when called from an
|
|
* interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with
|
|
* the page cache in this case.
|
|
*/
|
|
vm_page_t
|
|
vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
|
|
{
|
|
vm_object_t m_object;
|
|
vm_page_t m = NULL;
|
|
int color, flags, page_req, s;
|
|
|
|
page_req = req & VM_ALLOC_CLASS_MASK;
|
|
|
|
if ((req & VM_ALLOC_NOOBJ) == 0) {
|
|
KASSERT(object != NULL,
|
|
("vm_page_alloc: NULL object."));
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
KASSERT(!vm_page_lookup(object, pindex),
|
|
("vm_page_alloc: page already allocated"));
|
|
color = (pindex + object->pg_color) & PQ_L2_MASK;
|
|
} else
|
|
color = pindex & PQ_L2_MASK;
|
|
|
|
/*
|
|
* The pager is allowed to eat deeper into the free page list.
|
|
*/
|
|
if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) {
|
|
page_req = VM_ALLOC_SYSTEM;
|
|
};
|
|
|
|
s = splvm();
|
|
loop:
|
|
mtx_lock_spin(&vm_page_queue_free_mtx);
|
|
if (cnt.v_free_count > cnt.v_free_reserved ||
|
|
(page_req == VM_ALLOC_SYSTEM &&
|
|
cnt.v_cache_count == 0 &&
|
|
cnt.v_free_count > cnt.v_interrupt_free_min) ||
|
|
(page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0)) {
|
|
/*
|
|
* Allocate from the free queue if the number of free pages
|
|
* exceeds the minimum for the request class.
|
|
*/
|
|
m = vm_pageq_find(PQ_FREE, color, (req & VM_ALLOC_ZERO) != 0);
|
|
} else if (page_req != VM_ALLOC_INTERRUPT) {
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
/*
|
|
* Allocatable from cache (non-interrupt only). On success,
|
|
* we must free the page and try again, thus ensuring that
|
|
* cnt.v_*_free_min counters are replenished.
|
|
*/
|
|
vm_page_lock_queues();
|
|
if ((m = vm_page_select_cache(color)) == NULL) {
|
|
vm_page_unlock_queues();
|
|
splx(s);
|
|
#if defined(DIAGNOSTIC)
|
|
if (cnt.v_cache_count > 0)
|
|
printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count);
|
|
#endif
|
|
atomic_add_int(&vm_pageout_deficit, 1);
|
|
pagedaemon_wakeup();
|
|
return (NULL);
|
|
}
|
|
KASSERT(m->dirty == 0, ("Found dirty cache page %p", m));
|
|
m_object = m->object;
|
|
VM_OBJECT_LOCK_ASSERT(m_object, MA_OWNED);
|
|
vm_page_busy(m);
|
|
pmap_remove_all(m);
|
|
vm_page_free(m);
|
|
vm_page_unlock_queues();
|
|
if (m_object != object)
|
|
VM_OBJECT_UNLOCK(m_object);
|
|
goto loop;
|
|
} else {
|
|
/*
|
|
* Not allocatable from cache from interrupt, give up.
|
|
*/
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
splx(s);
|
|
atomic_add_int(&vm_pageout_deficit, 1);
|
|
pagedaemon_wakeup();
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* At this point we had better have found a good page.
|
|
*/
|
|
|
|
KASSERT(
|
|
m != NULL,
|
|
("vm_page_alloc(): missing page on free queue\n")
|
|
);
|
|
|
|
/*
|
|
* Remove from free queue
|
|
*/
|
|
|
|
vm_pageq_remove_nowakeup(m);
|
|
|
|
/*
|
|
* Initialize structure. Only the PG_ZERO flag is inherited.
|
|
*/
|
|
flags = PG_BUSY;
|
|
if (m->flags & PG_ZERO) {
|
|
vm_page_zero_count--;
|
|
if (req & VM_ALLOC_ZERO)
|
|
flags = PG_ZERO | PG_BUSY;
|
|
}
|
|
m->flags = flags;
|
|
if (req & VM_ALLOC_WIRED) {
|
|
atomic_add_int(&cnt.v_wire_count, 1);
|
|
m->wire_count = 1;
|
|
} else
|
|
m->wire_count = 0;
|
|
m->hold_count = 0;
|
|
m->act_count = 0;
|
|
m->busy = 0;
|
|
m->valid = 0;
|
|
KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m));
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
|
|
/*
|
|
* vm_page_insert() is safe prior to the splx(). Note also that
|
|
* inserting a page here does not insert it into the pmap (which
|
|
* could cause us to block allocating memory). We cannot block
|
|
* anywhere.
|
|
*/
|
|
if ((req & VM_ALLOC_NOOBJ) == 0)
|
|
vm_page_insert(m, object, pindex);
|
|
else
|
|
m->pindex = pindex;
|
|
|
|
/*
|
|
* Don't wakeup too often - wakeup the pageout daemon when
|
|
* we would be nearly out of memory.
|
|
*/
|
|
if (vm_paging_needed())
|
|
pagedaemon_wakeup();
|
|
|
|
splx(s);
|
|
return (m);
|
|
}
|
|
|
|
/*
|
|
* vm_wait: (also see VM_WAIT macro)
|
|
*
|
|
* Block until free pages are available for allocation
|
|
* - Called in various places before memory allocations.
|
|
*/
|
|
void
|
|
vm_wait(void)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_lock_queues();
|
|
if (curproc == pageproc) {
|
|
vm_pageout_pages_needed = 1;
|
|
msleep(&vm_pageout_pages_needed, &vm_page_queue_mtx,
|
|
PDROP | PSWP, "VMWait", 0);
|
|
} else {
|
|
if (!vm_pages_needed) {
|
|
vm_pages_needed = 1;
|
|
wakeup(&vm_pages_needed);
|
|
}
|
|
msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PVM,
|
|
"vmwait", 0);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_waitpfault: (also see VM_WAITPFAULT macro)
|
|
*
|
|
* Block until free pages are available for allocation
|
|
* - Called only in vm_fault so that processes page faulting
|
|
* can be easily tracked.
|
|
* - Sleeps at a lower priority than vm_wait() so that vm_wait()ing
|
|
* processes will be able to grab memory first. Do not change
|
|
* this balance without careful testing first.
|
|
*/
|
|
void
|
|
vm_waitpfault(void)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_lock_queues();
|
|
if (!vm_pages_needed) {
|
|
vm_pages_needed = 1;
|
|
wakeup(&vm_pages_needed);
|
|
}
|
|
msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PUSER,
|
|
"pfault", 0);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_activate:
|
|
*
|
|
* Put the specified page on the active list (if appropriate).
|
|
* Ensure that act_count is at least ACT_INIT but do not otherwise
|
|
* mess with it.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_activate(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
s = splvm();
|
|
if (m->queue != PQ_ACTIVE) {
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
cnt.v_reactivated++;
|
|
vm_pageq_remove(m);
|
|
if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
|
|
if (m->act_count < ACT_INIT)
|
|
m->act_count = ACT_INIT;
|
|
vm_pageq_enqueue(PQ_ACTIVE, m);
|
|
}
|
|
} else {
|
|
if (m->act_count < ACT_INIT)
|
|
m->act_count = ACT_INIT;
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_free_wakeup:
|
|
*
|
|
* Helper routine for vm_page_free_toq() and vm_page_cache(). This
|
|
* routine is called when a page has been added to the cache or free
|
|
* queues.
|
|
*
|
|
* This routine may not block.
|
|
* This routine must be called at splvm()
|
|
*/
|
|
static __inline void
|
|
vm_page_free_wakeup(void)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
/*
|
|
* if pageout daemon needs pages, then tell it that there are
|
|
* some free.
|
|
*/
|
|
if (vm_pageout_pages_needed &&
|
|
cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) {
|
|
wakeup(&vm_pageout_pages_needed);
|
|
vm_pageout_pages_needed = 0;
|
|
}
|
|
/*
|
|
* wakeup processes that are waiting on memory if we hit a
|
|
* high water mark. And wakeup scheduler process if we have
|
|
* lots of memory. this process will swapin processes.
|
|
*/
|
|
if (vm_pages_needed && !vm_page_count_min()) {
|
|
vm_pages_needed = 0;
|
|
wakeup(&cnt.v_free_count);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_page_free_toq:
|
|
*
|
|
* Returns the given page to the PQ_FREE list,
|
|
* disassociating it with any VM object.
|
|
*
|
|
* Object and page must be locked prior to entry.
|
|
* This routine may not block.
|
|
*/
|
|
|
|
void
|
|
vm_page_free_toq(vm_page_t m)
|
|
{
|
|
int s;
|
|
struct vpgqueues *pq;
|
|
vm_object_t object = m->object;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
s = splvm();
|
|
cnt.v_tfree++;
|
|
|
|
if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
|
|
printf(
|
|
"vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n",
|
|
(u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0,
|
|
m->hold_count);
|
|
if ((m->queue - m->pc) == PQ_FREE)
|
|
panic("vm_page_free: freeing free page");
|
|
else
|
|
panic("vm_page_free: freeing busy page");
|
|
}
|
|
|
|
/*
|
|
* unqueue, then remove page. Note that we cannot destroy
|
|
* the page here because we do not want to call the pager's
|
|
* callback routine until after we've put the page on the
|
|
* appropriate free queue.
|
|
*/
|
|
vm_pageq_remove_nowakeup(m);
|
|
vm_page_remove(m);
|
|
|
|
/*
|
|
* If fictitious remove object association and
|
|
* return, otherwise delay object association removal.
|
|
*/
|
|
if ((m->flags & PG_FICTITIOUS) != 0) {
|
|
splx(s);
|
|
return;
|
|
}
|
|
|
|
m->valid = 0;
|
|
vm_page_undirty(m);
|
|
|
|
if (m->wire_count != 0) {
|
|
if (m->wire_count > 1) {
|
|
panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx",
|
|
m->wire_count, (long)m->pindex);
|
|
}
|
|
panic("vm_page_free: freeing wired page\n");
|
|
}
|
|
|
|
/*
|
|
* If we've exhausted the object's resident pages we want to free
|
|
* it up.
|
|
*/
|
|
if (object &&
|
|
(object->type == OBJT_VNODE) &&
|
|
((object->flags & OBJ_DEAD) == 0)
|
|
) {
|
|
struct vnode *vp = (struct vnode *)object->handle;
|
|
|
|
if (vp) {
|
|
VI_LOCK(vp);
|
|
if (VSHOULDFREE(vp))
|
|
vfree(vp);
|
|
VI_UNLOCK(vp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Clear the UNMANAGED flag when freeing an unmanaged page.
|
|
*/
|
|
if (m->flags & PG_UNMANAGED) {
|
|
m->flags &= ~PG_UNMANAGED;
|
|
}
|
|
|
|
if (m->hold_count != 0) {
|
|
m->flags &= ~PG_ZERO;
|
|
m->queue = PQ_HOLD;
|
|
} else
|
|
m->queue = PQ_FREE + m->pc;
|
|
pq = &vm_page_queues[m->queue];
|
|
mtx_lock_spin(&vm_page_queue_free_mtx);
|
|
pq->lcnt++;
|
|
++(*pq->cnt);
|
|
|
|
/*
|
|
* Put zero'd pages on the end ( where we look for zero'd pages
|
|
* first ) and non-zerod pages at the head.
|
|
*/
|
|
if (m->flags & PG_ZERO) {
|
|
TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
|
|
++vm_page_zero_count;
|
|
} else {
|
|
TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
|
|
}
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
vm_page_free_wakeup();
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_unmanage:
|
|
*
|
|
* Prevent PV management from being done on the page. The page is
|
|
* removed from the paging queues as if it were wired, and as a
|
|
* consequence of no longer being managed the pageout daemon will not
|
|
* touch it (since there is no way to locate the pte mappings for the
|
|
* page). madvise() calls that mess with the pmap will also no longer
|
|
* operate on the page.
|
|
*
|
|
* Beyond that the page is still reasonably 'normal'. Freeing the page
|
|
* will clear the flag.
|
|
*
|
|
* This routine is used by OBJT_PHYS objects - objects using unswappable
|
|
* physical memory as backing store rather then swap-backed memory and
|
|
* will eventually be extended to support 4MB unmanaged physical
|
|
* mappings.
|
|
*/
|
|
void
|
|
vm_page_unmanage(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if ((m->flags & PG_UNMANAGED) == 0) {
|
|
if (m->wire_count == 0)
|
|
vm_pageq_remove(m);
|
|
}
|
|
vm_page_flag_set(m, PG_UNMANAGED);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_wire:
|
|
*
|
|
* Mark this page as wired down by yet
|
|
* another map, removing it from paging queues
|
|
* as necessary.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_wire(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
/*
|
|
* Only bump the wire statistics if the page is not already wired,
|
|
* and only unqueue the page if it is on some queue (if it is unmanaged
|
|
* it is already off the queues).
|
|
*/
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->wire_count == 0) {
|
|
if ((m->flags & PG_UNMANAGED) == 0)
|
|
vm_pageq_remove(m);
|
|
atomic_add_int(&cnt.v_wire_count, 1);
|
|
}
|
|
m->wire_count++;
|
|
KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m));
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_unwire:
|
|
*
|
|
* Release one wiring of this page, potentially
|
|
* enabling it to be paged again.
|
|
*
|
|
* Many pages placed on the inactive queue should actually go
|
|
* into the cache, but it is difficult to figure out which. What
|
|
* we do instead, if the inactive target is well met, is to put
|
|
* clean pages at the head of the inactive queue instead of the tail.
|
|
* This will cause them to be moved to the cache more quickly and
|
|
* if not actively re-referenced, freed more quickly. If we just
|
|
* stick these pages at the end of the inactive queue, heavy filesystem
|
|
* meta-data accesses can cause an unnecessary paging load on memory bound
|
|
* processes. This optimization causes one-time-use metadata to be
|
|
* reused more quickly.
|
|
*
|
|
* BUT, if we are in a low-memory situation we have no choice but to
|
|
* put clean pages on the cache queue.
|
|
*
|
|
* A number of routines use vm_page_unwire() to guarantee that the page
|
|
* will go into either the inactive or active queues, and will NEVER
|
|
* be placed in the cache - for example, just after dirtying a page.
|
|
* dirty pages in the cache are not allowed.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_unwire(vm_page_t m, int activate)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->wire_count > 0) {
|
|
m->wire_count--;
|
|
if (m->wire_count == 0) {
|
|
atomic_subtract_int(&cnt.v_wire_count, 1);
|
|
if (m->flags & PG_UNMANAGED) {
|
|
;
|
|
} else if (activate)
|
|
vm_pageq_enqueue(PQ_ACTIVE, m);
|
|
else {
|
|
vm_page_flag_clear(m, PG_WINATCFLS);
|
|
vm_pageq_enqueue(PQ_INACTIVE, m);
|
|
}
|
|
}
|
|
} else {
|
|
panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
|
|
/*
|
|
* Move the specified page to the inactive queue. If the page has
|
|
* any associated swap, the swap is deallocated.
|
|
*
|
|
* Normally athead is 0 resulting in LRU operation. athead is set
|
|
* to 1 if we want this page to be 'as if it were placed in the cache',
|
|
* except without unmapping it from the process address space.
|
|
*
|
|
* This routine may not block.
|
|
*/
|
|
static __inline void
|
|
_vm_page_deactivate(vm_page_t m, int athead)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
/*
|
|
* Ignore if already inactive.
|
|
*/
|
|
if (m->queue == PQ_INACTIVE)
|
|
return;
|
|
|
|
s = splvm();
|
|
if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
cnt.v_reactivated++;
|
|
vm_page_flag_clear(m, PG_WINATCFLS);
|
|
vm_pageq_remove(m);
|
|
if (athead)
|
|
TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
|
|
else
|
|
TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
|
|
m->queue = PQ_INACTIVE;
|
|
vm_page_queues[PQ_INACTIVE].lcnt++;
|
|
cnt.v_inactive_count++;
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
vm_page_deactivate(vm_page_t m)
|
|
{
|
|
_vm_page_deactivate(m, 0);
|
|
}
|
|
|
|
/*
|
|
* vm_page_try_to_cache:
|
|
*
|
|
* Returns 0 on failure, 1 on success
|
|
*/
|
|
int
|
|
vm_page_try_to_cache(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->dirty || m->hold_count || m->busy || m->wire_count ||
|
|
(m->flags & (PG_BUSY|PG_UNMANAGED))) {
|
|
return (0);
|
|
}
|
|
vm_page_test_dirty(m);
|
|
if (m->dirty)
|
|
return (0);
|
|
vm_page_cache(m);
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* vm_page_try_to_free()
|
|
*
|
|
* Attempt to free the page. If we cannot free it, we do nothing.
|
|
* 1 is returned on success, 0 on failure.
|
|
*/
|
|
int
|
|
vm_page_try_to_free(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->object != NULL)
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (m->dirty || m->hold_count || m->busy || m->wire_count ||
|
|
(m->flags & (PG_BUSY|PG_UNMANAGED))) {
|
|
return (0);
|
|
}
|
|
vm_page_test_dirty(m);
|
|
if (m->dirty)
|
|
return (0);
|
|
vm_page_busy(m);
|
|
pmap_remove_all(m);
|
|
vm_page_free(m);
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* vm_page_cache
|
|
*
|
|
* Put the specified page onto the page cache queue (if appropriate).
|
|
*
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_cache(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
|
|
m->hold_count || m->wire_count) {
|
|
printf("vm_page_cache: attempting to cache busy page\n");
|
|
return;
|
|
}
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
return;
|
|
|
|
/*
|
|
* Remove all pmaps and indicate that the page is not
|
|
* writeable or mapped.
|
|
*/
|
|
pmap_remove_all(m);
|
|
if (m->dirty != 0) {
|
|
panic("vm_page_cache: caching a dirty page, pindex: %ld",
|
|
(long)m->pindex);
|
|
}
|
|
s = splvm();
|
|
vm_pageq_remove_nowakeup(m);
|
|
vm_pageq_enqueue(PQ_CACHE + m->pc, m);
|
|
vm_page_free_wakeup();
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_dontneed
|
|
*
|
|
* Cache, deactivate, or do nothing as appropriate. This routine
|
|
* is typically used by madvise() MADV_DONTNEED.
|
|
*
|
|
* Generally speaking we want to move the page into the cache so
|
|
* it gets reused quickly. However, this can result in a silly syndrome
|
|
* due to the page recycling too quickly. Small objects will not be
|
|
* fully cached. On the otherhand, if we move the page to the inactive
|
|
* queue we wind up with a problem whereby very large objects
|
|
* unnecessarily blow away our inactive and cache queues.
|
|
*
|
|
* The solution is to move the pages based on a fixed weighting. We
|
|
* either leave them alone, deactivate them, or move them to the cache,
|
|
* where moving them to the cache has the highest weighting.
|
|
* By forcing some pages into other queues we eventually force the
|
|
* system to balance the queues, potentially recovering other unrelated
|
|
* space from active. The idea is to not force this to happen too
|
|
* often.
|
|
*/
|
|
void
|
|
vm_page_dontneed(vm_page_t m)
|
|
{
|
|
static int dnweight;
|
|
int dnw;
|
|
int head;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
dnw = ++dnweight;
|
|
|
|
/*
|
|
* occassionally leave the page alone
|
|
*/
|
|
if ((dnw & 0x01F0) == 0 ||
|
|
m->queue == PQ_INACTIVE ||
|
|
m->queue - m->pc == PQ_CACHE
|
|
) {
|
|
if (m->act_count >= ACT_INIT)
|
|
--m->act_count;
|
|
return;
|
|
}
|
|
|
|
if (m->dirty == 0)
|
|
vm_page_test_dirty(m);
|
|
|
|
if (m->dirty || (dnw & 0x0070) == 0) {
|
|
/*
|
|
* Deactivate the page 3 times out of 32.
|
|
*/
|
|
head = 0;
|
|
} else {
|
|
/*
|
|
* Cache the page 28 times out of every 32. Note that
|
|
* the page is deactivated instead of cached, but placed
|
|
* at the head of the queue instead of the tail.
|
|
*/
|
|
head = 1;
|
|
}
|
|
_vm_page_deactivate(m, head);
|
|
}
|
|
|
|
/*
|
|
* Grab a page, waiting until we are waken up due to the page
|
|
* changing state. We keep on waiting, if the page continues
|
|
* to be in the object. If the page doesn't exist, allocate it.
|
|
*
|
|
* This routine may block.
|
|
*/
|
|
vm_page_t
|
|
vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
|
|
{
|
|
vm_page_t m;
|
|
int s, generation;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
retrylookup:
|
|
if ((m = vm_page_lookup(object, pindex)) != NULL) {
|
|
vm_page_lock_queues();
|
|
if (m->busy || (m->flags & PG_BUSY)) {
|
|
generation = object->generation;
|
|
|
|
s = splvm();
|
|
while ((object->generation == generation) &&
|
|
(m->busy || (m->flags & PG_BUSY))) {
|
|
vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
|
|
VM_OBJECT_UNLOCK(object);
|
|
msleep(m, &vm_page_queue_mtx, PDROP | PVM, "pgrbwt", 0);
|
|
VM_OBJECT_LOCK(object);
|
|
if ((allocflags & VM_ALLOC_RETRY) == 0) {
|
|
splx(s);
|
|
return NULL;
|
|
}
|
|
vm_page_lock_queues();
|
|
}
|
|
vm_page_unlock_queues();
|
|
splx(s);
|
|
goto retrylookup;
|
|
} else {
|
|
if (allocflags & VM_ALLOC_WIRED)
|
|
vm_page_wire(m);
|
|
vm_page_busy(m);
|
|
vm_page_unlock_queues();
|
|
return m;
|
|
}
|
|
}
|
|
|
|
m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY);
|
|
if (m == NULL) {
|
|
VM_OBJECT_UNLOCK(object);
|
|
VM_WAIT;
|
|
VM_OBJECT_LOCK(object);
|
|
if ((allocflags & VM_ALLOC_RETRY) == 0)
|
|
return NULL;
|
|
goto retrylookup;
|
|
}
|
|
|
|
return m;
|
|
}
|
|
|
|
/*
|
|
* Mapping function for valid bits or for dirty bits in
|
|
* a page. May not block.
|
|
*
|
|
* Inputs are required to range within a page.
|
|
*/
|
|
__inline int
|
|
vm_page_bits(int base, int size)
|
|
{
|
|
int first_bit;
|
|
int last_bit;
|
|
|
|
KASSERT(
|
|
base + size <= PAGE_SIZE,
|
|
("vm_page_bits: illegal base/size %d/%d", base, size)
|
|
);
|
|
|
|
if (size == 0) /* handle degenerate case */
|
|
return (0);
|
|
|
|
first_bit = base >> DEV_BSHIFT;
|
|
last_bit = (base + size - 1) >> DEV_BSHIFT;
|
|
|
|
return ((2 << last_bit) - (1 << first_bit));
|
|
}
|
|
|
|
/*
|
|
* vm_page_set_validclean:
|
|
*
|
|
* Sets portions of a page valid and clean. The arguments are expected
|
|
* to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
|
|
* of any partial chunks touched by the range. The invalid portion of
|
|
* such chunks will be zero'd.
|
|
*
|
|
* This routine may not block.
|
|
*
|
|
* (base + size) must be less then or equal to PAGE_SIZE.
|
|
*/
|
|
void
|
|
vm_page_set_validclean(vm_page_t m, int base, int size)
|
|
{
|
|
int pagebits;
|
|
int frag;
|
|
int endoff;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (size == 0) /* handle degenerate case */
|
|
return;
|
|
|
|
/*
|
|
* If the base is not DEV_BSIZE aligned and the valid
|
|
* bit is clear, we have to zero out a portion of the
|
|
* first block.
|
|
*/
|
|
if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
|
|
(m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
|
|
pmap_zero_page_area(m, frag, base - frag);
|
|
|
|
/*
|
|
* If the ending offset is not DEV_BSIZE aligned and the
|
|
* valid bit is clear, we have to zero out a portion of
|
|
* the last block.
|
|
*/
|
|
endoff = base + size;
|
|
if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
|
|
(m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
|
|
pmap_zero_page_area(m, endoff,
|
|
DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
|
|
|
|
/*
|
|
* Set valid, clear dirty bits. If validating the entire
|
|
* page we can safely clear the pmap modify bit. We also
|
|
* use this opportunity to clear the PG_NOSYNC flag. If a process
|
|
* takes a write fault on a MAP_NOSYNC memory area the flag will
|
|
* be set again.
|
|
*
|
|
* We set valid bits inclusive of any overlap, but we can only
|
|
* clear dirty bits for DEV_BSIZE chunks that are fully within
|
|
* the range.
|
|
*/
|
|
pagebits = vm_page_bits(base, size);
|
|
m->valid |= pagebits;
|
|
#if 0 /* NOT YET */
|
|
if ((frag = base & (DEV_BSIZE - 1)) != 0) {
|
|
frag = DEV_BSIZE - frag;
|
|
base += frag;
|
|
size -= frag;
|
|
if (size < 0)
|
|
size = 0;
|
|
}
|
|
pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
|
|
#endif
|
|
m->dirty &= ~pagebits;
|
|
if (base == 0 && size == PAGE_SIZE) {
|
|
pmap_clear_modify(m);
|
|
vm_page_flag_clear(m, PG_NOSYNC);
|
|
}
|
|
}
|
|
|
|
void
|
|
vm_page_clear_dirty(vm_page_t m, int base, int size)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->dirty &= ~vm_page_bits(base, size);
|
|
}
|
|
|
|
/*
|
|
* vm_page_set_invalid:
|
|
*
|
|
* Invalidates DEV_BSIZE'd chunks within a page. Both the
|
|
* valid and dirty bits for the effected areas are cleared.
|
|
*
|
|
* May not block.
|
|
*/
|
|
void
|
|
vm_page_set_invalid(vm_page_t m, int base, int size)
|
|
{
|
|
int bits;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
bits = vm_page_bits(base, size);
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->valid &= ~bits;
|
|
m->dirty &= ~bits;
|
|
m->object->generation++;
|
|
}
|
|
|
|
/*
|
|
* vm_page_zero_invalid()
|
|
*
|
|
* The kernel assumes that the invalid portions of a page contain
|
|
* garbage, but such pages can be mapped into memory by user code.
|
|
* When this occurs, we must zero out the non-valid portions of the
|
|
* page so user code sees what it expects.
|
|
*
|
|
* Pages are most often semi-valid when the end of a file is mapped
|
|
* into memory and the file's size is not page aligned.
|
|
*/
|
|
void
|
|
vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
|
|
{
|
|
int b;
|
|
int i;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
/*
|
|
* Scan the valid bits looking for invalid sections that
|
|
* must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
|
|
* valid bit may be set ) have already been zerod by
|
|
* vm_page_set_validclean().
|
|
*/
|
|
for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
|
|
if (i == (PAGE_SIZE / DEV_BSIZE) ||
|
|
(m->valid & (1 << i))
|
|
) {
|
|
if (i > b) {
|
|
pmap_zero_page_area(m,
|
|
b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
|
|
}
|
|
b = i + 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* setvalid is TRUE when we can safely set the zero'd areas
|
|
* as being valid. We can do this if there are no cache consistancy
|
|
* issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
|
|
*/
|
|
if (setvalid)
|
|
m->valid = VM_PAGE_BITS_ALL;
|
|
}
|
|
|
|
/*
|
|
* vm_page_is_valid:
|
|
*
|
|
* Is (partial) page valid? Note that the case where size == 0
|
|
* will return FALSE in the degenerate case where the page is
|
|
* entirely invalid, and TRUE otherwise.
|
|
*
|
|
* May not block.
|
|
*/
|
|
int
|
|
vm_page_is_valid(vm_page_t m, int base, int size)
|
|
{
|
|
int bits = vm_page_bits(base, size);
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (m->valid && ((m->valid & bits) == bits))
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* update dirty bits from pmap/mmu. May not block.
|
|
*/
|
|
void
|
|
vm_page_test_dirty(vm_page_t m)
|
|
{
|
|
if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
|
|
vm_page_dirty(m);
|
|
}
|
|
}
|
|
|
|
int so_zerocp_fullpage = 0;
|
|
|
|
void
|
|
vm_page_cowfault(vm_page_t m)
|
|
{
|
|
vm_page_t mnew;
|
|
vm_object_t object;
|
|
vm_pindex_t pindex;
|
|
|
|
object = m->object;
|
|
pindex = m->pindex;
|
|
vm_page_busy(m);
|
|
|
|
retry_alloc:
|
|
vm_page_remove(m);
|
|
/*
|
|
* An interrupt allocation is requested because the page
|
|
* queues lock is held.
|
|
*/
|
|
mnew = vm_page_alloc(object, pindex, VM_ALLOC_INTERRUPT);
|
|
if (mnew == NULL) {
|
|
vm_page_insert(m, object, pindex);
|
|
vm_page_unlock_queues();
|
|
VM_OBJECT_UNLOCK(object);
|
|
VM_WAIT;
|
|
VM_OBJECT_LOCK(object);
|
|
vm_page_lock_queues();
|
|
goto retry_alloc;
|
|
}
|
|
|
|
if (m->cow == 0) {
|
|
/*
|
|
* check to see if we raced with an xmit complete when
|
|
* waiting to allocate a page. If so, put things back
|
|
* the way they were
|
|
*/
|
|
vm_page_busy(mnew);
|
|
vm_page_free(mnew);
|
|
vm_page_insert(m, object, pindex);
|
|
} else { /* clear COW & copy page */
|
|
if (!so_zerocp_fullpage)
|
|
pmap_copy_page(m, mnew);
|
|
mnew->valid = VM_PAGE_BITS_ALL;
|
|
vm_page_dirty(mnew);
|
|
vm_page_flag_clear(mnew, PG_BUSY);
|
|
}
|
|
}
|
|
|
|
void
|
|
vm_page_cowclear(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->cow) {
|
|
m->cow--;
|
|
/*
|
|
* let vm_fault add back write permission lazily
|
|
*/
|
|
}
|
|
/*
|
|
* sf_buf_free() will free the page, so we needn't do it here
|
|
*/
|
|
}
|
|
|
|
void
|
|
vm_page_cowsetup(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->cow++;
|
|
pmap_page_protect(m, VM_PROT_READ);
|
|
}
|
|
|
|
#include "opt_ddb.h"
|
|
#ifdef DDB
|
|
#include <sys/kernel.h>
|
|
|
|
#include <ddb/ddb.h>
|
|
|
|
DB_SHOW_COMMAND(page, vm_page_print_page_info)
|
|
{
|
|
db_printf("cnt.v_free_count: %d\n", cnt.v_free_count);
|
|
db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count);
|
|
db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count);
|
|
db_printf("cnt.v_active_count: %d\n", cnt.v_active_count);
|
|
db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count);
|
|
db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved);
|
|
db_printf("cnt.v_free_min: %d\n", cnt.v_free_min);
|
|
db_printf("cnt.v_free_target: %d\n", cnt.v_free_target);
|
|
db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min);
|
|
db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
|
|
{
|
|
int i;
|
|
db_printf("PQ_FREE:");
|
|
for (i = 0; i < PQ_L2_SIZE; i++) {
|
|
db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
|
|
}
|
|
db_printf("\n");
|
|
|
|
db_printf("PQ_CACHE:");
|
|
for (i = 0; i < PQ_L2_SIZE; i++) {
|
|
db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
|
|
}
|
|
db_printf("\n");
|
|
|
|
db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n",
|
|
vm_page_queues[PQ_ACTIVE].lcnt,
|
|
vm_page_queues[PQ_INACTIVE].lcnt);
|
|
}
|
|
#endif /* DDB */
|